“Reduction” is a cooking technique wherein a liquid is reduced in volume by boiling. Reduction is often used to thicken or intensify the flavor of a liquid mixture, such as a soup, sauce, syrup, wine, or juice. Reduction is often performed by boiling a liquid in a container without a lid or cover, thereby allowing vapor to escape and the volume of liquid to decrease to a desired level.
A cook may reduce a liquid using guesswork, simply by observing a boiling liquid in a container and reducing the applied heat when he or she estimates that the liquid has been reduced by the proper amount. A need exists for a device capable of indicating to a cook in a more precise and quantifiable manner that a liquid has indeed been reduced to the preferred predetermined level.